His comments came as he was interviewed on BBC London News about a row over the cap on housing benefits.

Newham Council, in East London, was said to have attempted to relocate families out of the area and place them with a housing association 160 miles away in Stoke-on-Trent.

Mr Johnson said he was against housing minister and Welwyn Hatfield MP Mr Shapps’ cap of £250 a week for a one-bedroom property (including shared accommodation); £290 a week for a two-bedroom property; £340 a week for a three-bedroom property; and £400 a week for a four-bedroom property.

Asked whether he would tell Mr Shapps if he was wrong, the Mayor said: “I will certainly tell Grant Shapps that he’s wrong if he does anything to jeopardise the interests of London.”

In response, Mr Shapps told the Welwyn Hatfield Times: “Boris rightly says he’d be against me doing anything to jeopardise the interests of London. I absolutely agree, and would never want to do that.

“All we’re saying is that hard working families paying their taxes must not be paying for people to be able to live in neighbourhoods that they themselves could never afford.

“That’s just unfair.”

He added: “Everyone might want to live in the finest street, in the best neighbourhood in Mayfair, although I personally don’t, but that doesn’t mean there’s a right to do so with others paying your rent.”

He also said it was wrong to say the Government was reducing the total housing benefit spend.

“In fact it’s projected to go from £21bn per year to £23bn by 2015.

“What we are doing is ensuring that it doesn’t rise even faster to £25bn,” he said.